Acting U.S. Defense Secretary Patrick Shanahan will meet China's defense minister at an Asia defense forum in Singapore, a senior U.S. defense official said Friday, at a time of strained relations between Beijing and Washington over trade and security.

Tensions between China and the United States have intensified in the past year, over an ongoing trade war and over the disputed South China Sea and U.S. support for self-ruled Taiwan, which China claims as its own.

"We're doing a pull aside (meeting) with the Chinese counterpart at Shangri-La," said the official, speaking on the condition of anonymity.

Chinese Defense Minister Wei Fenghe will deliver a speech on June 2 at the Shangri-La Dialogue, the first time since 2011 that a Chinese defense chief will be at the forum, having in recent years sent lower level officials.

"We've got a relationship with China that contains elements of both competition and cooperation," the senior U.S. defense official said.

Shanahan's predecessor, Jim Mattis, met Wei in Singapore last year.

Separately Friday, the Pentagon said U.S. and Chinese officials met in Washington earlier this week.

"The dialogue emphasized a constructive, results-oriented military relationship with a focus on maintaining open and clear communication, especially in times of crisis," a Pentagon statement said. The two sides discussed topics that included South China Sea and North Korea.